Automatic guidewire maneuvering system and method

ABSTRACT

System for guiding a catheter through a lumen system of a body of a patient, to a predetermined location within the lumen system, the system including a medical positioning system, a moving mechanism coupled with the catheter, and a controller coupled with the medical positioning system and with the moving mechanism, the medical positioning system including at least one position detector, the position detector being firmly attached to a distal portion of the catheter, the medical positioning system determining the position of the position detector, the controller controlling the operation of the moving mechanism to move the catheter to the predetermined location, according to the position and according to a topological representation of at least a portion of the lumen system.

FIELD OF THE DISCLOSED TECHNIQUE

The disclosed technique relates to medical equipment in general, and tomethods and systems for maneuvering a catheter within a lumen of a bodyof a patient, in particular.

BACKGROUND OF THE DISCLOSED TECHNIQUE

Various diagnostic and medical operations on lumens of the body of apatient, such as the circulation system, the gastrointestinal tract, thebrain vessels, the bronchial tree, and the like, are preformed byinserting a catheter through the lumen. Since the catheter is generallya bulky device, it is difficult to guide it to the operational site allon its own. For this purpose, a guidewire whose diameter issubstantially smaller than that of the catheter, is inserted to theoperational site before inserting the catheter, and then the catheter ispassed over the guidewire and guided to the operational site.

Methods and systems for maneuvering the guidewire through the lumen tothe operational site, are known in the art. Generally, the operatormanipulates the movements of the guidewire, by manually pushing orpulling the guidewire or twisting the guidewire, while he watches animage of the tip of the guidewire, against a real time two-dimensionalimage of the lumen (e.g., by employing a fluoroscopy angiogram). In thismanner, the tip of the guidewire is maneuvered at various bifurcationsof the lumens, in order to reach the operational site. The same methodis employed for manipulating a catheter, only that a marker (e.g., anX-ray opaque material) is located on the tip of the catheter.

U.S. Pat. No. 6,594,517 B1 issued to Nevo and entitled “Method andApparatus for Generating Controlled Torques on Objects ParticularlyObjects Inside a Living Body”, is directed to a system and method forapplying a controlled torque on an intra-body device, to bend the tip ofthe intra-body device. The system includes an input device, a processingand control unit, and electronic-interface, the intra-body device, atorque generating module, a location and direction module and a magneticresonance imaging system (MRI). The MRI includes a computer, an imagedisplay, a gradient activation control unit, an MRI magnet, and a set ofthree orthogonal gradient coils. The torque generating module includesthree micro-coils.

The processing and control unit is connected with the input device, theelectronic interface, the computer, and with the gradient activationcontrol unit. The torque generating module and the location anddirection module are located at the tip of the intra-body device. Thetorque generating module and the location and direction module areconnected with the electronic interface. The computer is connected withthe image display and with the gradient activation control unit. Thegradient activation control unit is connected with the orthogonalgradient coils.

The processing and control unit controls the electrical currents throughthe micro-coils, in order to cause the torque generating module togenerate a resultant magnetic dipole to interact with the magnetic fieldproduced by the MRI magnet. This interaction produces a torque of thedesired direction and magnitude, in order to steer the tip of theintra-body device. The gradient activation control unit provides theprocessing and control unit, information respective of theelectromagnetic gradient fields generated by the three orthogonalgradient coils, and the timing sequence of the activation of thesecoils. The image display provides a real time image of the operationfield. The location and direction module provides the location anddirection or orientation of the tip of the intra-body device. Thecomputer provides the processing and control unit, the event schedule ofthe MRI system, to prevent image artifacts due to activation of thetorque generating module, when the MRI magnets are activated forimaging.

A stereotaxis system is employed for steering a guidewire of a catheterthrough the lumen, and bending the tip of the guidewire, by applying amagnetic field to the guidewire through a plurality of magnets. Magneticfields are applied to cause the guidewire to turn in differentdirections. U.S. Pat. No. 6,035,856 describes such a method.

U.S. Pat. No. 6,035,856 issued to LaFontaine et al., and entitled“Percutaneous Bypass with Branching Vessel”, is directed to a method forperforming a bypass on a first occlusion of a branching vessel of theaorta. A coronary artery which includes the first occlusion, and abranching vessel branch out of the aorta. A standard guide-catheter isadvanced through the aorta up to the ostium of the branching vessel. Anocclusion forming device is advanced through the guide-catheter into thebranching vessel, to produce a second occlusion in the branching vessel.The occlusion device includes an elongate portion and a heated balloon.

The occlusion forming device is removed from the aorta through theguide-catheter and a cutting device is advanced through theguide-catheter proximal to the second occlusion. The cutting deviceincludes an elongate member, a steerable guidewire, a proximal occlusionballoon, a distal balloon, a stent, a cutting blade, a first piece ofmagnetic material and a transmitter. The cutting blade is located distalto the distal balloon, the first piece of the magnetic material islocated between the cutting blade and the distal balloon and thetransmitter is located within the distal balloon. The distal balloon islocated within the stent. The transmitter emits radio frequency signals.

The wall of the branching vessel is cut by employing the cutting blade.The distal balloon is kept in the expanded position, in order to occludethe branching vessel after the branching vessel has been cut. Thesevered end of the branching vessel is steered toward a region of thecoronary artery distal to the first occlusion, by maneuvering thesteerable guidewire or by manipulating the first piece of the magneticmaterial by a second piece of magnetic material, wherein the secondpiece of magnetic material is located outside the body of the patient.

The true position and the relative position of the transmitter and thusthe position of the severed end of the branching vessel, is determinedby employing a triangulation and coordinate mapping system. Thetriangulation and coordinate mapping system includes three referenceelectrodes which are located outside the body of the patient. Two of thereference electrodes are located on opposite sides of the heart and thethird is located on the back. The three reference electrodes are used totriangulate on the transmitter.

When the severed end of the branching vessel is properly positioned, anaperture is formed in the coronary artery distal to the first occlusion,by employing the cutting blade. The severed end of the branching vesselis inserted into the coronary artery through the aperture and the stentis expanded by inflating the distal balloon, thereby attaching thesevered end of the branching vessel to the lumen of the coronary artery.

SUMMARY OF THE DISCLOSED TECHNIQUE

It is an object of the disclosed technique to provide a novel method andsystem for using a feedback from a position sensor located on the tip ofa wire (or a catheter), to automatically maneuver and guide the tip ofthe catheter to a predefined designated position based on a structuralroadmap of the vessel tree.

In accordance with the disclosed technique, there is thus provided asystem for guiding a catheter through a lumen system of a body of apatient, to a predetermined location within the lumen system. The systemincludes a medical positioning system, a moving mechanism coupled withthe catheter, and a controller coupled with the medical positioningsystem and with the moving mechanism.

The medical positioning system includes at least one position detector.The position detector is firmly attached to a distal portion of thecatheter. The medical positioning system determines the position of theposition detector. The controller controls the operation of the movingmechanism to move the catheter to the predetermined location, accordingto the determined position and according to a topological representationof at least a portion of the lumen system.

In accordance with another aspect of the disclosed technique there isthus provided a method for guiding a catheter to a predeterminedlocation within a lumen system of a body of a patient. The methodincludes the procedures of determining a new position to move thecatheter to, according to a position signal received respective of afirst position of a distal portion of the catheter, and according to atopological representation of the lumen system, and operating a movingmechanism to move the catheter to a second position, according to thenew determined position.

The method further includes the procedure of receiving the positionsignal and performing the operating procedure, when the second positionis substantially identical with the new determined position, anddetermining at least one corrective movement, when the second positionis not identical with the new determined position. The method furtherincludes the procedure of directing the moving mechanism to move thecatheter according to the determined corrective movement.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed technique will be understood and appreciated more fullyfrom the following detailed description taken in conjunction with thedrawings in which:

FIG. 1 is a schematic illustration of a system for automaticallymaneuvering a catheter within a lumen of the body of a patient,constructed and operative in accordance with an embodiment of thedisclosed technique;

FIG. 2 is a schematic illustration of a method by which the imagingsystem of the system of FIG. 1 determines the coordinates of a pathwithin the lumen, in three dimensions; and

FIG. 3 is a schematic illustration of a method for operating the systemof FIG. 1, operative in accordance with another embodiment of thedisclosed technique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The disclosed technique overcomes the disadvantages of the prior art byproviding a system which automatically controls the movements of acatheter to a desired location within a lumen of a patient, according toa path within the lumen and according to the current position of the tipof the catheter within the lumen, while employing the current positionas a feedback to control the movement. The path which the tip of thecatheter is to follow is preplanned and is determined at an imagingsession prior to the operational session, by employing a dynamic imager.Alternatively, the system maneuvers the catheter within the lumen, tothe desired location, according to the circulation map of the body ofthe patient. The operator can override the automatic operation of thesystem and revert to the manual mode at any time, while observing arepresentation of the tip of the catheter against a real timetwo-dimensional image of the lumen. An organ monitor, such as anelectrocardiogram (ECG) for monitoring an organ timing signal of anorgan can be employed with the system, to display the two-dimensionalimage, as well as the three-dimensional structural model of the vesseltree by taking into account the movements of the lumen caused bypulsations of the organ (e.g., the heart).

The term “catheter” herein below, refers to an elongated body which canbe inserted to a lumen of the body of a patient. The catheter can be forexample, a guidewire for guiding a medical device to a certain locationwithin the lumen, and the like. The term “topological representation”herein below, refers to a mapping of a lumen system (e.g., thecirculation, the bronchial tree, the urogenital system, the renalsystem) of the body of the patient, which a system according to thedisclosed technique employs, in order to maneuver the catheter from anorigin to a destination. The mapping can be either two-dimensional orthree-dimensional. Alternatively, it is noted that the term “topologicalrepresentation” may include just the path to be followed in the lumensystem. The term “position” herein below, refers either to the location,to the orientation or both the location and the orientation, of anobject in a three-dimensional coordinate system.

Reference is now made to FIGS. 1 and 2. FIG. 1 is a schematicillustration of a system, generally referenced 100, for automaticallymaneuvering a catheter within a lumen of the body of a is patient,constructed and operative in accordance with an embodiment of thedisclosed technique. FIG. 2 is a schematic illustration of a method bywhich the imaging system of the system of FIG. 1 determines thecoordinates of a path within the lumen, in three dimensions.

With reference to FIG. 1, system 100 includes a joystick 102, acontroller 104, a moving mechanism 106, a medical positioning system(MPS) 108, a plurality of transmitters 110A, 110B and 110C, an imagingsystem 112, a position detector 114, a catheter 116 and a display 118.Imaging system 112 includes a radiation generator 120 and a radiationdetector 122. Imaging system 112 can be an X-ray system, fluoroscope,C-arm imager, computed tomography (CT), positron emission tomography(PET), ultrasound system, magnetic resonance imager (MRI), and the like.

Moving mechanism 106 can include a pair of angular movement rollers 124Aand 124B, and a pair of linear movement rollers 126A and 126B, andrespective moving elements (not shown) such as electric motors,actuators, and the like. However, moving mechanism 106 can includeother, alternative or additional elements, as long as it imparts tocatheter 116 the necessary motions described herein below (e.g.,piezoelectric motors which transfer linear movement through friction).Optionally, moving mechanism 106 can be disposable in order to keep itsterile. Controller 104 includes a processor (not shown) and a storageunit (not shown) for storing information respective of a path 128, whichcatheter 116 should move according to, within a lumen 130 of the body(not shown) of a patient (not shown).

Moving mechanism 106 is coupled with joystick 102 and with controller104. Controller 104 is coupled with imaging system 112. MPS 108 iscoupled with controller 104 and with transmitters 110A, 110B and 110C.Position detector 114 is coupled with MPS 108 by a conductor 132 (i.e.,a conductive coupling). Display 118 is coupled with MPS 108 and withimaging system 112. Position detector 114 is located at a distal portionof catheter 116.

During the medical operation, the body of the patient is located betweenradiation generator 120 and radiation detector 122. Imaging system 112has at least one degree of freedom, thereby being able to take aplurality of images of the body of the patient, from differentdirections. Imaging system 112 provides a signal to display 118,respective of a two-dimensional image 134 of lumen 130, for display 118to display two-dimensional image 134.

Path 128 is a three-dimensional curve between an origin 136 and adestination 138 of a distal portion (not shown) of catheter 116 relativeto lumen 130. Both origin 136 and destination 138 are within a field ofview of imaging system 112. Path 128 is determined during an imagingsession prior to the medical operation, and stored in the storage unit.

Controller 104 calculates and constructs path 128, for example,according to a plurality of two-dimensional images obtained from lumen130, with the aid of a C-arm imager. For example, the C-arm can obtaintwo two-dimensional ECG gated images of lumen 130 at two differentnon-parallel ECG gated image planes. When the user indicates origin 136and destination 138, the C-arm constructs path 128 in three dimensions.It is noted that controller 104 calculates path 128 based on one or moreimage processing algorithms, according to contrast variations of lumen130 relative to the background.

With further reference to FIG. 2, imaging system 112 captures an image144 of lumen 130 on an image plane 146 in a three-dimensional coordinatesystem 148, and another image 150 of lumen 130 on an image plane 152 inthree-dimensional coordinate system 148. Imaging system 112 is aware ofthe orientation between image planes 146 and 152 (i.e., the angles therebetween). Imaging system 112 identifies a feature 154 of lumen 130 inimage 144 and a corresponding feature 156 in image 150. Imaging system112 determines the three-dimensional coordinates of feature 154 (orfeature 156) in three-dimensional coordinate system 148, by determiningthe intersection of normals 158 and 160 from features 154 and 156,respectively, to image planes 146 and 152, respectively, at a point 162.Imaging system 112 performs the above procedure for other features oflumen 130, thereby constructing path 128 in three dimensions.

A two-dimensional image which the C-arm obtains from the body of thepatient, can include other lumens (not shown) in addition to lumen 130,which are located at planes different than the plane of lumen 130 (i.e.,these additional lumens overlap lumen 130 in the captured image). Inthis case, when the user indicates origin 136 and destination 138, it isnot evident to the C-arm that the user is interested in a path throughlumen 130, and the C-arm can construct a path (not shown), which passesthrough another lumen which in the two-dimensional image overlaps lumen130. Hence, the C-arm obtains another two-dimensional image of lumen 130at another image plane, such that in the new two-dimensional image,lumen 130 is not overlapped by any other lumens.

Prior to the medical operation, the coordinate systems of MPS 108 andimaging system 112 are set to a common two-dimensional coordinatesystem, for display 118 to superimpose a representation 140 of positiondetector 114, on two-dimensional image 134, during the medicaloperation. This method is described for example, in U.S. patentapplication Ser. No. 09/949,160, which is incorporated herewith byreference. The information displayed by display 118, serves the physicalstaff to observe the location of the distal portion of catheter 116relative to lumen 130, throughout the medical operation. Thistwo-dimensional coordinate system can be determined for example,according to the following method.

A first transformation model between the three-dimensional coordinatesystem of MPS 108 and the three-dimensional coordinate system of imagingsystem 112 is determined. A second transformation model between thethree-dimensional coordinate system of imaging system 112 and atwo-dimensional coordinate system of imaging system 112 is determined.The three-dimensional coordinate system of MPS 108 is transformed to thethree-dimensional coordinate system of imaging system 112, by applyingthe first transformation model to the three-dimensional coordinatesystem of MPS 108. The three-dimensional transformed coordinate systemof imaging system 112 is transformed to the two-dimensional coordinatesystem of imaging system 112, by applying the second transformationmodel to the three-dimensional transformed coordinate system of imagingsystem 112.

The first transformation model is determined according to a set ofpoints in the three-dimensional coordinate system of MPS 108 and anotherset of points in the three-dimensional coordinate system of imagingsystem 112. The second transformation model is determined according toexternal parameters of imaging system 112 (i.e., a set of points in thethree-dimensional coordinate system of imaging system 112) and internalparameters of imaging system 112 (e.g., lens angle, focal length,magnification).

Following is a description of operation of system 100, for performing anoperation on the vessels in the neck region of the patient. In thiscase, path 128 is a three-dimensional curve within the axillary artery(represented by lumen 130) which marks a path from the region of thefirst rib (i.e., origin 136) to the thyrocervical trunk (i.e.,destination 138). At the stage of medical operation, the physical staffinserts catheter 116 to the body of the patient through the rightbrachial artery (not shown), and manually maneuvers catheter 116 toreach origin 136.

At this point, system 100 takes over, to automatically maneuver catheter116 to destination 138. In response to the electromagnetic fieldproduced by transmitters 110A, 110B and 110C, position detector 114sends a signal to MPS 108 via conductor 132, respective of thethree-dimensional position of position detector 114. Alternatively,position detector 114 is coupled with MPS 108 wirelessly and withoutconductor 132, in which case position detector 114 sends this positionsignal to MPS 108 wirelessly.

MPS 108 determines the coordinates of position detector 114 according tothe signal received from position detector 114. MPS 108 sends a signalrespective of the coordinates of position detector 114 to controller104, in the three-dimensional coordinate system of MPS 108. MPS 108sends a signal respective of the coordinates of position detector 114 todisplay 118, in the two-dimensional coordinate system of imaging system112, as described herein above.

Throughout the medical operation, display 118 displays two-dimensionalimage 134 of an operational region of lumen 130 (i.e., a section betweenorigin 136 and destination 138) according to a signal received fromimaging system 112. Display 118 also displays representation 140 of thecurrent location of position detector 114 (i.e., the distal portion ofcatheter 116), superposed on two-dimensional image 134, according to thesignal received from MPS 108. Alternatively, the current location of theposition detector can be superposed on a three-dimensional image of thelumen (e.g., the coronary tree).

Instead of path 128, the controller can employ a topographicalrepresentation of the lumen system of the patient, in order to controlthe moving mechanism to maneuver the catheter through the lumen system,from an origin to a destination within the lumen system. In this case,the controller determines the best path for the catheter to reach thedestination. It is noted that the controller may change the path inreal-time, depending on findings during the navigation process (e.g.,blocked passages, lumen which is narrower than expected). The controllermodifies the path according to the feedback provided in real time by theposition detector, and by comparing the actual position and orientationof the position detector with the expected position and orientation.Furthermore, the controller modifies a predefined three-dimensional pathwhich is used as a three-dimensional roadmap for the planning process.

The system can further include a processor (not shown) coupled with theMPS and with the display, and an organ monitor (not shown) such as anECG coupled with the processor, as described in U.S. patent applicationSer. No. 09/949,160. The organ monitor monitors the organ timing signalof a monitored organ and sends a respective signal to the processor. Theprocessor sends a video signal to the display respective of an image ofthe lumen, corresponding with the current activity-state of themonitored organ detected by the organ monitor. The display displays animage of the lumen, according to the current activity-state. Thus, thedisplay displays a superposition of a representation of the positiondetector on a reconstructed image of the lumen, taking into account themovements of the lumen due to the timing signal of the monitored organ(e.g., the heart beat of the patient). The display can display athree-dimensional reconstructed image of the lumen, as described in U.S.patent application Ser. No. 09/949,160. This three-dimensionalreconstructed image is displayed relative to the coordinate system ofthe body of the patient.

Alternatively, the medical positioning system can filter out the organtiming signal (i.e., producing a filtered MPS reading) and the currentposition of the position detector in the coordinate system of the lumen,from a multitude of positions of the position detector, in thecoordinate system of the body of the patient. In this case, thecontroller updates the topological representation and the position ofthe tip of the catheter according to the filtered MPS reading. Thecontroller controls the moving mechanism according to the updatedtopological representation and the updated position of the catheter.Furthermore, the display can display the updated topologicalrepresentation and the updated representation of the distal portion ofthe catheter, superposed on a substantially stationary three-dimensionalreconstructed image of the lumen.

Moving mechanism 106 operates according to the commands received fromcontroller 104, to maneuver catheter 116 along path 128, from origin 136to destination 138. For this purpose, the pair of angular movementrollers 124A and 124B twist catheter 116 clockwise and counterclockwiserelative to the longitudinal axis (not shown) of catheter 116, and thepair of linear movement rollers 126A and 126B move catheter 116 forwardand backward. Controller 104 constantly receives a signal from MPS 108respective of three-dimensional coordinates of position detector 114 atany given time (i.e., a feedback), thereby allowing moving mechanism 106to apply corrections to possible errors of movement along path 128.These corrections are applied in the following manner.

Controller 104 sends a signal at predetermined time increments to movingmechanism 106, to advance catheter 116 by a predetermined displacementincrement. Controller 104 determines the advancement of the distalportion of catheter 116 at each time increment (according to theposition signal received from MPS 108), and checks whether thisadvancement substantially matches the predetermined displacement bywhich catheter 116 was supposed to advance. In case the actual detectedadvancement does not match the predetermined displacement increment,controller 104 determines that catheter 116 has made contact with anobstacle (not shown) which prevents catheter 116 to advance according topath 128 (e.g., the distal portion of catheter 116 can be stuck at abifurcation 142).

In this case, controller 104 sends a signal to moving mechanism 106 toretreat catheter 116 by a selected increment backward within lumen 118,and also to twist the distal portion of catheter 116 by a selectedamount. After this twist, controller 104 sends a signal to movingmechanism 106 to advance catheter 116 by a predetermined displacementincrement. Thus, moving mechanism 106 can maneuver catheter 116 toovercome the obstacle and to enter the predetermined branch (in thiscase the thyrocervical trunk at bifurcation 142).

It is noted that due to the three-dimensional position information whichcontroller 104 receives as a real time feedback from MPS 108, controller104 can control the operation of moving mechanism 106 to maneuvercatheter 116 in three-dimensions. Thus, system 100 provides an advantageover systems in the prior art, in which the physical staff can maneuverthe catheter according to a two-dimensional display, only in twodimensions. System 100 provides automatic maneuvering of catheter 116through lumen 130 in three dimensions, while performing feedbackoriented real time corrections in order to reach destination 138 withinlumen 130.

Imaging system 112 (e.g., a C-arm) can detect lumen 130 from differentdirections in order to provide the information necessary for display 118to display two-dimensional image 134. Imaging system 112 selects the onespecific imaging direction at which the average distance of path 128from an image plane (not shown), is minimal. If X_(i) is the distancefrom a point i on path 128 normal to the image plane, where i=1, 2, 3 .. . N, then the minimum average distance is,

$\begin{matrix}{\min\;\frac{\sum\limits_{1}^{N}X_{i}}{N}} & (1)\end{matrix}$In case path 128 follows many curves in space and deviates significantlyfrom a two-dimensional path, then imaging system 112 can divide path 128to different parts, and prepare the information for two-dimensionalimage 134, by selecting a different image plane for each part, whilesatisfying Equation 1.

It is noted that more than one position detector can be located at thedistal portion of the catheter. This arrangement is crucial in case thedistal portion of the catheter is provided with a “curve-back”functionality. The “curve-back” movement can be provided for example, byemploying Electro Active Polymers (EAP). The moving mechanism islikewise provided with the necessary elements to apply an appropriatetorque to the distal portion of the catheter, to bend the distalportion. Moreover, with the aid of multiple position detectors, thedisplay can display the current geometry of the distal portion.

Furthermore, the controller can obtain a more complete informationrespective of the geometry of the distal portion of the catheter, whenthe catheter is blocked by an obstacle, and thus expedite themaneuvering operation. For example, if the controller detects that thedistal portion of the catheter has unexpectedly bent, then thecontroller determines that the tip of the catheter has made contact withan obstacle in the lumen. The controller can reach this conclusion forexample, by comparing the detected orientation of the position detectorat a given point within the lumen, with the computed slope of the pathat the same point within the lumen. In case the detected orientation andthe computed slope do not match, the controller determines that thecatheter has met an obstacle, thereby directing the moving mechanism tooperate in order to move the catheter back from the obstacle.

In case the physical staff is unsatisfied with the automatic operationof moving mechanism 106, he can override controller 104, and manuallyoperate moving mechanism 106 via joystick 102. The operator canintervene in any phase of operation of system 100, using joystick 102.This is a semi-automatic mode of operation of system 100, whereincontroller 104 enables moving mechanism 106 to maneuver catheter 116through the trivial portions of path 128, and the operator takes controlof system 100 in the more intricate portions of path 128. In case ofmanual intervention, joystick 102 overcomes any automated action. Isnoted that both in the automatic mode and the manual mode, the operatorreceives a visual feedback of the advancement of catheter 116 withinlumen 130, by viewing representation 140 of the tip of catheter 116 ondisplay 118.

Reference is now made to FIG. 3, which is a schematic illustration of amethod for operating the system of FIG. 1, operative in accordance withanother embodiment of the disclosed technique. In procedure 170, asignal respective of a first position of the tip of a catheter within alumen system of a body of a patient is received. With reference to FIG.1, controller 104 receives a signal from MPS 108 respective of theposition of the distal portion of catheter 116, within lumen 130.

In procedure 172, a new position to move the catheter to, is determinedaccording to the received signal and according to a topologicalrepresentation of the lumen system. With reference to FIG. 1, controller104 determines a new position for catheter 116 within lumen 130,according to the current position, and according to path 128.

In procedure 174, a moving mechanism is operated to move the catheter toa second position, according to the new determined position. Withreference to FIG. 1, controller 104 sends a signal to moving mechanism106 to move catheter 116 within lumen 130, to a second position,according to the new position determined in procedure 172, in order toadvance catheter 116 within lumen 130 toward destination 138.

In procedure 176, it is determined whether the second position issubstantially identical with the new determined position. If the outcomeof the comparison is positive, then the method proceeds to procedure170. Otherwise the method proceeds to procedure 178.

With reference to FIG. 1, controller 104 constantly receives a signalrespective of the position of the tip of catheter 116 within lumen 130,and compares the current position with the position determined inprocedure 172. If controller 104 determines that the current position issubstantially identical with the one determined in procedure 172, thencontroller 104 determines that moving mechanism 106 has advancedcatheter 116 as originally planned in procedure 172. In this case,procedures 170, 172 and 174 are repeated.

With reference to FIG. 1, controller 104 determines that the currentposition of the tip of catheter 116 is not identical with the onedetermined in procedure 172. Thus, controller 104 determines thatcatheter 116 has reached an obstacle, such as bifurcation 142, whichprevents catheter 116 to advance within lumen 130 as planned inprocedure 172.

In procedure 178, at least one corrective movement for moving thecatheter is determined. With reference to FIG. 1, controller 104 forexample, determines that catheter 116 has to be retreated within lumen130 by a certain amount, twisted by a certain amount and then pushedforward within lumen 130, by a certain amount in order for catheter 116to clear bifurcation 142.

In procedure 180, the moving mechanism is directed to move the catheteraccording to the determined corrective movement. With reference to FIG.1, controller 104 for example, sends a signal to moving mechanism 106for linear movement rollers 126A and 126B to pull catheter 116 by aselected linear increment within lumen 130, and for angular movementrollers 124A and 124B to twist the tip of catheter 116 by a selectedamount. Controller 104 then sends a signal to moving mechanism 106 forlinear movement rollers 126A and 126B to push catheter 116 by anotherselected linear increment. The method can then return back to procedure170 to advance catheter 116 to another position toward destination 138within lumen 130.

It will be appreciated by persons skilled in the art that the disclosedtechnique is not limited to what has been particularly shown anddescribed hereinabove. Rather the scope of the disclosed technique isdefined only by the claims, which follow.

1. Method for guiding a catheter to a predetermined location within alumen system of a body of a patient, the method comprising the steps of:establishing a preplanned path in said lumen system from a topologicalrepresentation of the lumen system; determining a new first position ofsaid catheter in said preplanned path according to a position signalreceived respective of the first position of a distal portion of saidcatheter and also determining a new position to which said catheter isto be moved based on said determined first position and according tosaid preplanned path established from said topological representation;operating a moving mechanism to move said catheter to a second position,according to said new determined position; receiving said positionsignal and performing said operating step and when said second positionis substantially identical with said new determined position determininga further new position on said preplanned path to which said catheter isto be moved and when said second position is not identical with said newdetermined position determining a modified path that involves at leastone corrective movement for said catheter, wherein said at least onecorrective movement is determined, when the orientation of said distalportion at a certain location within said lumen system, is differentthan at least one slope of said three dimensional path at said certainlocation, and wherein said at least one corrective movement includesretreating said catheter backward within said lumen system, performingone of twisting and bending of said distal portion of said catheter andadvancing said catheter in said lumen system; and directing said movingmechanism to move said catheter according to said determined correctivemovement along said modified path to thereby overcome an obstruction insaid preplanned path; updating at least one of said topologicalrepresentation, said first position and said second position, accordingto an organ timing signal of an organ timing monitor coupled with amonitored organ of said body, said monitored organ being coupled withsaid lumen system; controlling said moving mechanism according to atleast one of said updated topological representation, said updated firstposition and said updated second position; superposing a representationof at least one of said updated first position and said updated secondposition on an image of at least a portion of said lumen system; anddisplaying said superposition wherein said displaying step includestransforming a three dimensional coordinate system of a medicalpositioning system for determining at least one of said first positionand said second position, to a two dimensional coordinate system of saidimage.
 2. The method for guiding a catheter according to claim 1,wherein said at least one corrective movement further includes twistingsaid distal portion of said catheter, when the advancement of saiddistal portion does not match the displacement of said catheter. 3.Method for guiding a catheter along a path to a predetermined locationwithin a lumen system of a body of a patient, the method comprising thesteps of: establishing a preplanned path in said lumen system from atopological representation of the lumen system; determining a new firstposition of said catheter in said preplanned path according to aposition signal received respective of the first position of a distalportion of said catheter and also determining a new position to whichsaid catheter is to be moved based on said determined first position andaccording to said preplanned path established from said topologicalrepresentation; operating a moving mechanism to move said catheter to asecond position, according to said new determined position; receivingsaid position signal and performing said operating step and when saidsecond position is substantially identical with said new determinedposition determining a further new position on said preplanned path towhich said catheter is to be moved and when said second position is notidentical with said new determined position determining a modified paththat involves at least one corrective movement for said catheter,wherein said at least one corrective movement is determined, when theorientation of said distal portion at a certain location within saidlumen system, is different than at least one slope of said threedimensional path at said certain location, and wherein said at least onecorrective movement includes retreating said catheter backward withinsaid lumen system, performing one of twisting and bending of said distalportion of said catheter and advancing said catheter in said lumensystem; and directing said moving mechanism to move said catheteraccording to said determined corrective movement along said modifiedpath to thereby overcome an obstruction in said preplanned path.
 4. Themethod according to claim 3, further comprising the step of: updating atleast one of said topological representation, said first position andsaid second position, according to an organ timing signal of an organtiming monitor coupled with a monitored organ of said body, saidmonitored organ being coupled with said lumen system; and controllingsaid moving mechanism according to at least one of said updatedtopological representation, said updated first position and said updatedsecond position.
 5. The method according to claim 3, wherein saidtopological representation is produced by indicating an origin and adestination of an image of at least a portion of said lumen, in acoordinate system respective of said body.
 6. The method according toclaim 3, further comprising imaging at least a portion of said lumensystem at least one image plane which is closest to said predeterminedpath, among a plurality of other image planes.
 7. The method accordingto claim 3, further comprising imaging at least a portion of said lumensystem at least one other image plane, when in at least one prior imageplane, at least a portion of at least one lumen system overlaps saidlumen system.
 8. The method according to claim 3, further comprisingdetermining the shape of said distal portion, according to a pluralityof position signals received respective of positions of a plurality ofposition detectors located at said distal portion, after performing saidprocedure of operating.
 9. The method according to claim 3, wherein saidat least one corrective movement is selected from the group consistingof: along a longitudinal axis of said catheter relative to at least aportion of said lumen; and about said longitudinal axis relative to saidat least one portion.